A series of synthetic sialosides were evaluated for their ability to interact with reovirus serotype 3. It was found that sialosides with terminal N-acetylneuraminic acid (NeuNAc) linked in either an alpha 2,3 or alpha 2,6 configuration effectively blocked the binding of reovirus to mouse L fibroblasts, in contrast to a monosaccharide mixture containing the oligosaccharide constituents. Direct binding of reovirus to the sialosides was also demonstrable using sialosides conjugated to bovine serum albumin as ligands in a solid phase binding system. Of particular significance was the finding that the conjugate containing alpha-sialic acid alone (linked to bovine serum albumin) was capable of being recognized by reovirus at a level comparable to that of the other sialoside conjugates. Virus binding was abrogated by pretreating such conjugates with neuraminidase. These results suggest that the alpha-anomeric form of sialic acid is the minimal receptor determinant for reovirus recognition.